core: Add initial token definitions

Signed-off-by: Ian Moffett <ian@mirocom.org>

inc/rifle/token.h

@@ -0,0 +1,28 @@
+#ifndef RIFLE_TOKEN_H
+#define RIFLE_TOKEN_H 1
+
+/*
+ * Represents valid token types
+ */
+typedef enum {
+    TT_NONE,    /* <NONE> */
+    TT_PLUS,    /* '+' */
+    TT_MINUS,   /* '-' */
+    TT_STAR,    /* '*' */
+    TT_SLASH,   /* '/' */
+} tt_t;
+
+/*
+ * Represents a single lexical element found within
+ * the source input.
+ *
+ * @type: Token type
+ */
+struct token {
+    tt_t type;
+    union {
+        char c;
+    };
+};
+
+#endif /* !RIFLE_TOKEN_H */